Lab 19

Case III:

T = rF where F = mg
Tnet = T1 – T2 = 0
T1 = T2
rF = rF =>
Unknown mass = (M2*x2)/x1

Mass:
D = .29kg % Error – 7.4 %
F = .22kg % Error – 15.8%
R = .15kg % Error - 15.4%
B = .28kg % Error – 7.7%
E = .22kg % Error – 4.8%

Case IV:

m1*x1 = m2*x2 where m1 = mass of meter stick

Assume weight acts at center of mass of meter stick. Assume 50cm mark is center of mass.

m1 = (m2*x2)/x1 = (.1kg*.26m)/.24 = .11kg

Actual mass of meter stick - .11kig

% Error = 0%

Questions:
  1. A large or small force can produce a large or small torque depending on the value of r-perpendicular. If a small force is applied at a 90 degree angle, it can easily produce a higher torque than a large force applied at at smaller angle.
  2. We do not include the “support force” in our calculations because its r value, or the distance from the axis is zero, causing it to produce no Torque.
  3. Tnet = T1 – T2 – Ts = 0 => T1 - T2 = Ts
    (m1*r1 – m2*r2)/rs = ms = .17kg